Buffer Overflow Affecting ruby:3.3/rubygem-mysql2 package, versions <0:0.5.5-1.module_el8.10.0+3799+191214cc


Severity

Recommended
high

Based on AlmaLinux security rating.

Threat Intelligence

EPSS
0.75% (53rd percentile)

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  • Snyk IDSNYK-ALMALINUX8-RUBY-19821634
  • published15 Sept 2026
  • disclosed5 Aug 2026

Introduced: 5 Aug 2026

CVE-2026-27820  (opens in a new tab)
CWE-120  (opens in a new tab)
CWE-131  (opens in a new tab)

How to fix?

Upgrade AlmaLinux:8 ruby:3.3/rubygem-mysql2 to version 0:0.5.5-1.module_el8.10.0+3799+191214cc or higher.
This issue was patched in ALSA-2026:50728.

NVD Description

Note: Versions mentioned in the description apply only to the upstream ruby:3.3/rubygem-mysql2 package and not the ruby:3.3/rubygem-mysql2 package as distributed by AlmaLinux. See How to fix? for AlmaLinux:8 relevant fixed versions and status.

zlib is a Ruby interface for the zlib compression/decompression library. Versions 3.0.0 and below, 3.1.0, 3.1.1, 3.2.0 and 3.2.1 contain a buffer overflow vulnerability in the Zlib::GzipReader. The zstream_buffer_ungets function prepends caller-provided bytes ahead of previously produced output but fails to guarantee the backing Ruby string has enough capacity before the memmove shifts the existing data. This can lead to memory corruption when the buffer length exceeds capacity. This issue has been fixed in versions 3.0.1, 3.1.2 and 3.2.3.

CVSS Base Scores

version 3.1